RESUMO
A series of 1-O-acyl- and 1-oxo-kamebanin analogues were prepared from kamebanin, isolated from Rabdosia excisa and their cytotoxicity was assayed on HL60 promyelocytic leukemia cells and HCT116 human colon cancer cells. The structure-activity relationship study showed that the presence of 1-O-acyl groups of a C3-C5 carbon chain increased the cytotoxic activity.
Assuntos
Antineoplásicos , Isodon , Humanos , Antineoplásicos/farmacologia , Relação Estrutura-Atividade , Células HL-60 , Células HCT116RESUMO
We designed and synthesized a chiral ligand N-(anthracen-9-ylmethyl)-1-(pyridin-2-yl)-N-(pyridin-2-ylmethyl)ethanamine (APPE) DNA photocleavage agent to investigate the effects of chirality of bis(2-picolyl)amine on the DNA photocleavage activity of metal complexes. The structures of ZnII and CoII complexes in APPE were analyzed via X-ray crystallography and fluorometric titration. APPE formed metal complexes with a 1 : 1 stoichiometry in both the crystalline and solution states. Fluorometric titration was used to show that the ZnII and CoII association constants of these complexes (log Kas) were 4.95 and 5.39, respectively. The synthesized complexes were found to cleave pUC19 plasmid DNA when irradiated at 370 nm. The DNA photocleavage activity of the ZnII complex was higher than that of the CoII complex. The absolute configuration of the methyl-attached carbon did not affect DNA cleavage activity and, unfortunately, an achiral APPE derivative without the methyl group (ABPM) was found to perform DNA photocleavage more effectively than APPE. One reason for this may be that the methyl group suppressed the structural flexibility of the photosensitizer. These results will be useful for the design of new photoreactive reagents.
Assuntos
Complexos de Coordenação , Zinco , Zinco/química , Cobalto/química , Complexos de Coordenação/farmacologia , Complexos de Coordenação/química , Cobre/química , Aminas/química , DNA/química , Cristalografia por Raios X , LigantesRESUMO
BACKGROUND: Anaesthesia and perioperative management contribute to long-term outcomes of patients with cancer, including pancreatic ductal adenocarcinoma. We assessed the antitumour, anti-inflammatory, and analgesic effects of midazolam on LSL-KrasG12D/+;Trp53flox/flox;Pdx-1cre/+ transgenic mice with pancreatic ductal adenocarcinoma. METHODS: Six-week-old transgenic mice were administered midazolam 30 mg kg-1 day-1 p.o. (n=13); midazolam 30 mg kg-1 day-1 with 1-(2-chlorophenyl)-N-methyl-N(1-methylpropyl)-3-isoquinoline carboxamide (PK11195) 3 mg kg-1 day-1 i.p., a peripheral benzodiazepine receptor antagonist (n=10); or vehicle (water; n=14) until the humane endpoint. Cancer-associated pain was evaluated using hunching score and mouse grimace scale. Tumour stage and immuno-inflammatory status were determined histopathologically. Anti-proliferative and apoptotic potentials of midazolam were investigated using mouse pancreatic ductal adenocarcinoma cell lines. RESULTS: Midazolam significantly inhibited tumour size and proliferative index of Ki-67 and cyclins in pancreatic ductal adenocarcinoma, which was blocked by administration of PK11195. Local myeloperoxidase+ tumour-associated neutrophils, arginase-1+ M2-like tumour-associated macrophages, and CD11b+Ly-6G+ polymorphonuclear myeloid-derived suppressor cells were reduced by midazolam, which was antagonised by administration of PK11195. Hunching and mouse grimace scale were improved by midazolam, whereas the scores increased with midazolam+PK11195 treatment. Plasma pro-inflammatory cytokines, such as interleukin-6 and CC chemokine ligand (CCL)2, CCL3, and CCL5, were reduced by midazolam, whereas these cytokines increased with PK11195. Midazolam inhibited pancreatic ductal adenocarcinoma proliferation through downregulation of cyclins and cyclin-dependent kinases and induced apoptosis in vitro. CONCLUSIONS: These results suggest that midazolam inhibits pancreatic ductal adenocarcinoma proliferation and local infiltration of tumour-associated neutrophils, tumour-associated macrophages, and polymorphonuclear myeloid-derived suppressor cells, thereby inhibiting pancreatic ductal adenocarcinoma progression.
Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Animais , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Modelos Animais de Doenças , Humanos , Camundongos , Camundongos Transgênicos , Midazolam/farmacologia , Midazolam/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológicoRESUMO
DNA-cleavage agents such as bleomycin have potential anticancer applications. The development of a DNA-cleavage reagent that recognizes specific sequences allows the development of cancer therapy with reduced side effects. In this study, to develop novel compounds with specific DNA-cleavage activities, we synthesized optically active binuclear ligands, (1R,1'R,2R,2'R)-N1,N1'-(meta/para-phenylenebis(methylene))bis(N2,N2-bis(pyridin-2-ylmethyl)cyclohexane-1,2-diamine) and their enantiomers. The DNA-cleavage activities of these compounds were investigated in the presence of Fe(II)SO4 and sodium ascorbate. The obtained results indicated that the Fe(II) complexes of those compounds efficiently cleave DNA and that their cleavage was subtle sequence-selective. Therefore, we succeeded in developing compounds that can be used as small-molecule drugs for cancer chemotherapy.
Assuntos
Cicloexilaminas/farmacologia , Compostos Ferrosos/farmacologia , Cicloexilaminas/síntese química , Cicloexilaminas/química , Clivagem do DNA , Relação Dose-Resposta a Droga , Compostos Ferrosos/síntese química , Compostos Ferrosos/química , Ligantes , Estrutura Molecular , Plasmídeos , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
It is necessary to design a ligand that is compatible with the target molecule to optimally use the DNA-cleaving ability of metal complexes. In this study, we synthesized an optically active dinuclear ligand, (1R,1'R,2R,2'R)-N1,N1'-(anthracene-1,8-diylbis(methylene))bis(N2,N2-bis(pyridin-2-ylmethyl)cyclohexane-1,2-diamine) (R-ABDC, 4a) and its enantiomer (S-ABDC, 4b). We then prepared their Fe(II) complexes by mixing the ligand with FeSO4·7H2O in situ and investigated DNA-cleaving activities using plasmid DNA in the presence of excess sodium ascorbate at atmospheric conditions. The Fe(II) complexes efficiently cleaved DNA and selectively recognized two consecutive A and/or T sequences.
Assuntos
DNA/efeitos dos fármacos , Desenho de Fármacos , Compostos Ferrosos/farmacologia , Clivagem do DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Compostos Ferrosos/síntese química , Compostos Ferrosos/química , Ligantes , Estrutura Molecular , Plasmídeos , Relação Estrutura-AtividadeRESUMO
Lithium cations were observed to accelerate the hydrolysis of esters with hydroxides (KOH, NaOH, LiOH) in a water/tetrahydrofuran (THF) two-phase system. Yields in the hydrolysis of substituted benzoates and aliphatic esters using the various hydroxides were compared, and the effects of the addition of lithium salt were examined. Moreover, it was presumed that a certain amount of LiOH was dissolved in THF by the coordination of THF with lithium cation and hydrolyzed esters even in the THF layer, as in the reaction by a phase-transfer catalyst.
Assuntos
Furanos/química , Lítio/química , Catálise , Cátions/química , Ésteres/química , Hidrólise , Hidróxidos/química , Água/químicaRESUMO
Hepatocellular carcinoma (HCC) is a disease with poor prognosis. Nuclear accumulation of YB-1 is closely related to the malignancy of HCC. Treatment with anticancer agents often induces translocation of YB-1 from cytoplasm to nucleus and activates the expression of multidrug resistance gene 1 (MDR1). Therefore, any effective inhibitor of this phenomenon would be useful for cancer treatment. Here we examined various indirubin derivatives and found that indirubin 3'-oxime inhibits actinomycin D-induced nuclear transport of YB-1 and suppresses the activation of MDR1 gene expression in the human hepatocellular carcinoma cell line HepG2. Furthermore, use of both indirubin 3'-oxime and actinomycin D in combination increased the anticancer effect on HepG2 cells. Indirubin 3'-oxime is a novel and efficient inhibitor of anticancer agent-induced YB-1 nuclear translocation.
Assuntos
Antineoplásicos/administração & dosagem , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/metabolismo , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Indóis/administração & dosagem , Oximas/administração & dosagem , Proteína 1 de Ligação a Y-Box/metabolismo , Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Inibidores da Angiogênese/administração & dosagem , Carcinoma Hepatocelular/patologia , Núcleo Celular/patologia , Relação Dose-Resposta a Droga , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Células Hep G2 , HumanosRESUMO
When multiple drugs or chemicals are used in combination, it is important to understand the risk of their interactions and predict potential additive effects. The aim of the current study was to investigate the molecular mechanism(s) accounting for the additive/synergistic effect of combination treatment with acetaminophen (APAP) and carbon tetrachloride (CCl4). Mice were intraperitoneally administered vehicle or 100 mg/kg (5 mL/kg) APAP and 30 min after vehicle or 15 mg/kg (5 mL/kg) CCl4. Sixteen hours after treatment, mice from each group were sacrificed and the livers were removed. CCl4 administration caused slight glycogen depletion; this effect was more pronounced following co-administration of APAP and CCl4. ATP and NADPH levels showed the same trend as glycogen levels. The levels of receptor interacting protein 1 and 3 increased following combination treatment with APAP and CCl4. In contrast, levels of the glutamate cysteine ligase catalytic subunit and glutamate cysteine ligase modifier subunits were not significantly affected by combination treatment. APAP and CCl4 co-administration potentiated the phosphorylation of c-Jun N-terminal kinase and p38 kinases, although phosphorylated activation of extracellular signal-regulated kinase was not changed. Our results suggest that APAP and CCl4 co-administration potentiates hepatotoxicity in an additive/synergistic manner via receptor interacting protein activation.
Assuntos
Acetaminofen/toxicidade , Tetracloreto de Carbono/toxicidade , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Fígado/efeitos dos fármacos , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Acetaminofen/administração & dosagem , Animais , Tetracloreto de Carbono/administração & dosagem , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/patologia , Modelos Animais de Doenças , Sinergismo Farmacológico , Fígado/metabolismo , Fígado/patologia , Masculino , Camundongos EndogâmicosRESUMO
BACKGROUND: The current study aimed to investigate the hepatoprotective effects of Sasa veitchii extract (SE) on carbon tetrachloride (CCl4)-induced liver fibrosis in mice. METHODS: Male C57BL/6J mice were intraperitoneally injected with CCl4 dissolved in olive oil (1 g/kg) twice per week for 8 weeks. SE (0.1 mL) was administered orally once per day throughout the study, and body weight was measured weekly. Seventy-two hours after the final CCl4 injection, mice were euthanized and plasma samples were collected. The liver and kidneys were collected and weighed. RESULTS: CCl4 administration increased liver weight, decreased body weight, elevated plasma alanine aminotransferase, and aspartate aminotransferase and increased liver oxidative stress (malondialdehyde and glutathione). These increases were attenuated by SE treatment. Overexpression of tumor necrosis factor-α was also reversed following SE treatment. Furthermore, CCl4-induced increases in α-smooth muscle actin, a marker for hepatic fibrosis, were attenuated in mice treated with SE. Moreover, SE inhibited CCl4-induced nuclear translocation of hepatic nuclear factor kappa B (NF-κB) p65 and phosphorylation of mitogen-activated protein kinase (MAPK). CONCLUSION: These results suggested that SE prevented CCl4-induced hepatic fibrosis by inhibiting the MAPK and NF-κB signaling pathways.
Assuntos
Tetracloreto de Carbono/toxicidade , Cirrose Hepática/tratamento farmacológico , Extratos Vegetais/farmacologia , Substâncias Protetoras/farmacologia , Sasa/química , Animais , Cirrose Hepática/induzido quimicamente , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Distribuição AleatóriaRESUMO
Indirubin and its derivatives have been reported to exhibit anti-cancer and anti-inflammatory activities. Recently, some of its derived analogs have been shown to have neuroprotective potential. Endoplasmic reticulum (ER) stress has been demonstrated to contribute to the pathogenesis of various neurodegenerative diseases, whereas the effects of indirubin derivatives on ER stress-induced cell death have not been addressed. In the present study, a series of 44 derivatives of indirubin was prepared to search for a novel class of neuroprotective agents against ER stress-induced neuronal death. The MTT reduction assay indicated that tunicamycin (TM), an inducer of ER stress, significantly decreased the viability of hippocampal neuronal HT22 cells. Among the compounds tested, eight showed significant inhibitory activity against TM-induced cell death. Western blot analysis showed that application of these analogs to the cells simultaneously with TM reduced the TM-induced expression of CHOP, an established mediator of ER stress. Our results suggest that the preventive effect of these indirubin derivatives against ER stress-induced neuronal death may be due, at least in part, to attenuation of the CHOP-dependent signaling system.
Assuntos
Regulação para Baixo/efeitos dos fármacos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Substâncias Protetoras/farmacologia , Fator de Transcrição CHOP/metabolismo , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Indóis/química , Indóis/farmacologia , Camundongos , Substâncias Protetoras/química , Relação Estrutura-Atividade , Tunicamicina/toxicidadeRESUMO
Indirubin 3'-oxime (Indox (1b)) suppresses cancer cell growth (IC50: 15µM towards HepG2 cells) and inhibits cell cycle-related kinases such as cyclin-dependent kinases and glycogen synthase kinase-3ß. We have previously reported that the conjugation of 1b with oxirane, a protein-reactive component, enhanced the cytotoxic activity of Indox as determined from the IC50 value (1.7µM) of indirubin 3'-(O-oxiran-2-ylmethyl)oxime (Epox/Ind (1c)). Here we prepared Epox/Ind derivatives with one or two halogen atoms or a methoxy group on the aromatic ring(s) of an Indox moiety and studied the structure-activity relationships of the substituent(s). We found that bromine-substitution at the 5-position on 1c or any Epox/Ind derivative(s) having bromine on the aromatic ring except Epox/6'-Br-Ind was efficient to improving anticancer activity. Of the 22 Epox/Ind derivatives, 5-bromoindirubin 3'-(O-oxiran-2-ylmethyl)oxime (Epox/5-Br-Ind (2c)) was the best anticancer agent in both short- (24h) (IC50: 0.67µM) and extended-duration (72h) cultures. The high anticancer activity of 2c was partly due to it being a poor substrate and a suicide inhibitor for epoxide hydrolase as epoxide hydrolase was identified as the enzyme primarily responsible for the metabolism of 2c.
Assuntos
Antineoplásicos/química , Epóxido Hidrolases/antagonistas & inibidores , Indóis/química , Oximas/química , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Sítios de Ligação , Bromo/química , Sobrevivência Celular/efeitos dos fármacos , Epóxido Hidrolases/metabolismo , Células Hep G2 , Humanos , Indóis/metabolismo , Indóis/farmacologia , Cinética , Simulação de Acoplamento Molecular , Oximas/metabolismo , Oximas/farmacologia , Estrutura Terciária de Proteína , Relação Estrutura-AtividadeRESUMO
Indirubin inhibits cyclin-dependent kinases by binding to their ATP-binding site, thereby exerting potent cytotoxicity on some tumor cells. We examined the anti-tumor effect of indirubin 3'-epoxide on human neuroblastoma cell lines (IMR-32, SK-N-SH, and NB-39). The results revealed potent cytotoxicity of indirubin 3'-epoxide against the IMR-32 (IC50: 0.16 µM) and SK-N-SH (IC50: 0.07 µM) cells. Furthermore, it also induced an increase of the sub-G1 population in the IMR-32 cells. Examination by Hoechst 33342 staining revealed apoptosis characterized by cell shrinkage, nuclear condensation and nuclear fragmentation in a concentration-dependent manner. Furthermore, annexin V-propidium iodide (PI) double-staining revealed an increase in the percentage of early apoptotic cells following treatment of the cells with indirubin 3'-epoxide without activation of caspases. In addition, significant decreases in the protein level of survivin and poly(ADP-ribose)polymerase (PARP), and increase in that of apoptosis-inducing factor (AIF) were found in the nuclei of the cells. These results suggest that indirubin 3'-epoxide induced caspase-independent apoptosis through mechanisms involving DNA fragmentation and inhibition of DNA repair.
Assuntos
Antineoplásicos/farmacologia , Indóis/farmacologia , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/metabolismo , Caspases/metabolismo , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Fragmentação do DNA , Humanos , Neuroblastoma/patologiaRESUMO
Indirubin is a potent inhibitor of cell cycle-related protein kinases by binding to the ATP-binding site and thus is a promising compound for development as an antitumor drug. We prepared indirubin 3'-(O-oxiran-2-ylmethyl)oxime (Epox/Ind), in which the ATP-binding site orientated part was attached by non-specific alkylating group. The IC50 value of Epox/Ind at 1.7 µM in HepG2 cells is comparable to that of cisplatin (4.0 µM). Furthermore, Epox/Ind was shown to be metabolized by a HepG2 cell lysate into indirubin 3'-(O-2,3-dihydroxypropyl)oxime (E804), the sole extractable metabolite. The lower toxicity of this metabolite may explain the lack of cytotoxicity of 1 µM Epox/Ind observed in HepG2 cells beyond an initial loss of viability in the first 24h of treatment.
Assuntos
Antineoplásicos/farmacologia , Indóis/farmacologia , Oximas/farmacologia , Antineoplásicos/química , Antineoplásicos/metabolismo , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células Hep G2 , Humanos , Indóis/síntese química , Indóis/química , Estrutura Molecular , Oximas/síntese química , Oximas/química , Relação Estrutura-AtividadeRESUMO
In the structure of the title complex, [Zn(C4H2FN2O2)(C10H24N4)]ClO4, the zinc(II) ion forms coordination bonds with the four nitro-gen atoms of cyclam (1,4,8,11-tetra-aza-cyclo-tetra-decane or [14]aneN4) as well as with the nitro-gen atom of a deprotonated 5-fluoro-uracil ion (FU-). Cyclam adopts a trans-I type conformation within this structure. The coordination structure of the zinc(II) ion is a square pyramid with a distorted base plane formed by the four nitro-gen atoms of the cyclam. FU- engages in inter-molecular hydrogen bonding with neighboring FU- mol-ecules and with the cyclam mol-ecule.
RESUMO
In the title salt, [ZnCl(C23H30N4)]NO3, the central ZnII atom of the complex cation is coordinated in a square-pyramidal arrangement by four nitro-gen atoms from cyclen (1,4,7,10-tetra-aza-cyclo-dodeca-ne) in the basal plane and one chlorido ligand in the apical position. The anthracene group attached to cyclen contributes to the crystal packing through inter-molecular T-shaped π inter-actions. Additionally, the nitrate anion participates in inter-molecular N-Hâ¯O hydrogen bonds with cyclen.
RESUMO
INTRODUCTION: Tramadol, a weak opioid anesthetic, is used for pain management in patients with cancer, but the effects of tramadol on cancer via µ-opioid receptor are still unknown. We assessed the effects of tramadol on pancreatic ductal adenocarcinoma using transgenic mice (LSL-KrasG12D/+; Trp53flox/flox; Pdx-1cre/+ ). METHODS: Six-week-old transgenic mice were orally administered 10 mg/kg/day tramadol (n=12), 10 mg/kg/day tramadol and 1 mg/kg/day naltrexone (n=9), or vehicle water (n=14) until the humane endpoint. Cancer-related pain and plasma cytokine levels were assessed by the mouse grimace scale and cytokine array, respectively. Tumor status was determined histopathologically. Tramadol's effects on proliferation and invasion in pancreatic ductal adenocarcinoma cell lines were studied in vitro. RESULTS: Tramadol with/without naltrexone improved mouse grimace scale scores while decreasing inflammatory cytokines such as tumor necrosis factor-α and interleukin-6. Proliferative Ki-67 and cyclins decreased by tramadol, while local M1-like tumor-associated macrophages increased by tramadol, which was blocked by naltrexone. Meanwhile, tramadol with/without naltrexone reduced juxta-tumoral cancer-associated fibroblasts and M2-like tumor-associated macrophages. Tumor-associated neutrophils, natural killers, and cytotoxic T cells were not altered. Tramadol decreased the proliferative and invasive potentials of pancreatic ductal adenocarcinoma cell lines via decreasing cyclins/cyclin-dependent kinases, which was partially reversed by naltrexone. CONCLUSIONS: These findings imply that tramadol might be a useful anesthetic for pancreatic ductal adenocarcinoma: inhibiting the proliferation and invasion along with increasing antitumor M1-like tumor-associated macrophages via the µ-opioid receptor, while improving cancer-associated pain possibly through the antitumor effects with the decrease of inflammatory cytokines.
Assuntos
Anestésicos , Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Tramadol , Humanos , Camundongos , Animais , Tramadol/farmacologia , Tramadol/uso terapêutico , Naltrexona , Receptores Opioides , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/metabolismo , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Camundongos Transgênicos , Citocinas , CiclinasRESUMO
ABSTRACT: Mirogabalin, a selective voltage-gated calcium channel α2δ ligand, improves peripheral neuropathic pain; however, its effects on patients with cancers including pancreatic ductal adenocarcinoma (PDAC) remain unknown. We analyzed the effects of mirogabalin on a KPPC ( LSL-KrasG12D/+; Trp53flox/flox; Pdx-1cre/+ ) mouse model of PDAC. Six-week-old KPPC mice received oral mirogabalin (10 mg/kg/day) (n = 10) or vehicle water (n = 14) until the humane end point. Cancer-associated pain was evaluated using the scores of hunching and mouse grimace scale (MGS). Tumor status and plasma cytokine levels were determined using histopathological analysis and cytokine array, respectively. The effects of mirogabalin on the proliferative ability of PDAC cell lines were determined. The scores of the hunching and MGS improved after mirogabalin administration with a decrease in the plasma levels of inflammatory cytokines, such as tumor necrosis factor-α, interleukin-6, and interferon-γ. Although no significant difference in the survival rate was observed, mirogabalin significantly increased pancreatic tumor size and proliferative index of Ki-67 and cyclins. Local arginase-1 + M2-like tumor-associated macrophages and CD31 + tumor blood vessels increased after mirogabalin administration. By contrast, the number of α-smooth muscle actin + cancer-associated fibroblasts, desmoplastic stroma, and CD8 + T cells decreased. Local myeloperoxidase + tumor-associated neutrophils and CD45R + B cells were unaltered. Mirogabalin enhanced the proliferative ability of PDAC cell lines with the upregulation of cyclins and cyclin-dependent kinases; however, it inhibited the potential of pancreatic stellate cells in vitro. Therefore, our results suggest that mirogabalin improves cancer-associated pain but enhances the proliferative potential of PDAC in vitro and in vivo.
Assuntos
Dor do Câncer , Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Camundongos , Animais , Dor do Câncer/tratamento farmacológico , Dor do Câncer/etiologia , Neoplasias Pancreáticas/complicações , Neoplasias Pancreáticas/tratamento farmacológico , Carcinoma Ductal Pancreático/complicações , Carcinoma Ductal Pancreático/tratamento farmacológico , Citocinas , Neoplasias PancreáticasRESUMO
In the title dinuclear CuII complex, [Cu2(NO3)(C24H46N8)(H2O)](NO3)3·3H2O, the two CuII mol-ecules both have a square-pyramidal geometry, but the ligands in the axial positions are different: a water mol-ecule and a nitrate ion. All nitrate ions, water mol-ecules, and N-H groups are involved in an inter-molecular hydrogen-bond network.
RESUMO
Gram-negative bacteria producing metallo-ß-lactamases (MBLs) have become a considerable threat to public health. MBLs including the IMP, VIM, and NDM types are Zn(II) enzymes that hydrolyze the ß-lactam ring present in a broad range of antibiotics, such as N-benzylpenicillin, meropenem, and imipenem. Among IMPs, IMP-1 and IMP-6 differ in a single amino acid substitution at position 262, where serine in IMP-1 is replaced by glycine in IMP-6, conferring a change in substrate specificity. To investigate how this mutation influences enzyme function, we examined lactamase inhibition by thiol compounds. Ethyl 3-mercaptopropionate acted as a competitive inhibitor of IMP-1, but a noncompetitive inhibitor of IMP-6. A comparison of the crystal structures previously reported for IMP-1 (PDB code: 5EV6) and IMP-6 (PDB code: 6LVJ) revealed a hydrogen bond between the side chain of Ser262 and Cys221 in IMP-1 but the absence of hydrogen bond in IMP-6, which affects the Zn2 coordination sphere in its active site. We investigated the demetallation rates of IMP-1 and IMP-6 in the presence of chelating agent ethylenediaminetetraacetic acid (EDTA) and found that the demetallation reactions had fast and slow phases with a first-order rate constant (kfast = 1.76 h-1, kslow = 0.108 h-1 for IMP-1, and kfast = 14.0 h-1 and kslow = 1.66 h-1 for IMP-6). The difference in the flexibility of the Zn2 coordination sphere between IMP-1 and IMP-6 may influence the demetallation rate, the catalytic efficiency against ß-lactam antibiotics, and the inhibitory effect of thiol compounds.
Assuntos
Antibacterianos , beta-Lactamases , beta-Lactamases/metabolismo , Domínio Catalítico , Substituição de Aminoácidos , Antibacterianos/farmacologia , beta-Lactamas/química , Zinco/química , Compostos de SulfidrilaRESUMO
The two ZnII atoms in the crystal structure of the title complex, [Zn(NO3)2(C10H24N4)]·CH3OH, have a distorted octa-hedral coordination sphere, defined by 1,4,8,11-tetra-aza-cyclo-tetra-decane (cyclam) N atoms in the equatorial plane and nitrate O atoms in the axial sites. The conformation of the cyclam is trans-III (R, R, S, S), which is typical for metal-cyclam complexes. Nitrate anions are involved in intra- and inter-molecular hydrogen bonding with the N-H groups of the ZnII-cyclam unit. Together with the methanol solvent mol-ecule, the hydrogen-bonding network connects the ZnII-cyclam units into ribbons running parallel to the a axis.